This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Host-tumor cell interactions are recognized to be critical in tumor development. We have shown that group VIA phospholipase A(2) [calcium-independent phospholipase A(2)[unreadable] (iPLA(2)[unreadable])] is important in regulating extracellular lysophosphatidic acid (LPA) levels around human epithelial ovarian cancer (EOC) cells. To explore the role of iPLA(2)[unreadable] in host-tumor cell interactions, we have used immunocompetent iPLA(2)[unreadable] knockout (iPLA(2)[unreadable](-/-)) mice and the mouse EOC cell line ID8.